// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/views/button_drag_utils.h"

#include "base/strings/utf_string_conversions.h"
#include "ui/base/dragdrop/drag_utils.h"
#include "ui/base/dragdrop/os_exchange_data.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/compositor/canvas_painter.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/vector2d.h"
#include "ui/gfx/image/image.h"
#include "ui/resources/grit/ui_resources.h"
#include "ui/views/background.h"
#include "ui/views/border.h"
#include "ui/views/controls/button/label_button.h"
#include "ui/views/controls/button/label_button_border.h"
#include "ui/views/drag_utils.h"
#include "ui/views/resources/grit/views_resources.h"
#include "ui/views/widget/widget.h"
#include "url/gurl.h"

namespace button_drag_utils {

// Maximum width of the link drag image in pixels.
static const int kLinkDragImageMaxWidth = 150;

void SetURLAndDragImage(const GURL& url,
    const base::string16& title,
    const gfx::ImageSkia& icon,
    const gfx::Point* press_pt,
    ui::OSExchangeData* data,
    views::Widget* widget)
{
    DCHECK(url.is_valid() && data);
    data->SetURL(url, title);
    SetDragImage(url, title, icon, press_pt, data, widget);
}

void SetDragImage(const GURL& url,
    const base::string16& title,
    const gfx::ImageSkia& icon,
    const gfx::Point* press_pt,
    ui::OSExchangeData* data,
    views::Widget* widget)
{
    // Create a button to render the drag image for us.
    views::LabelButton button(NULL,
        title.empty() ? base::UTF8ToUTF16(url.spec())
                      : title);
    button.SetTextSubpixelRenderingEnabled(false);
    const ui::NativeTheme* theme = widget->GetNativeTheme();
    button.SetTextColor(views::Button::STATE_NORMAL,
        theme->GetSystemColor(ui::NativeTheme::kColorId_TextfieldDefaultColor));

    SkColor bg_color = theme->GetSystemColor(
        ui::NativeTheme::kColorId_TextfieldDefaultBackground);
    if (widget->IsTranslucentWindowOpacitySupported()) {
        button.SetTextShadows(gfx::ShadowValues(
            10, gfx::ShadowValue(gfx::Vector2d(0, 0), 1.0f, bg_color)));
    } else {
        button.set_background(views::Background::CreateSolidBackground(bg_color));
        button.SetBorder(button.CreateDefaultBorder());
    }
    button.SetMaxSize(gfx::Size(kLinkDragImageMaxWidth, 0));
    if (icon.isNull()) {
        button.SetImage(views::Button::STATE_NORMAL,
            *ui::ResourceBundle::GetSharedInstance().GetImageNamed(
                                                        IDR_DEFAULT_FAVICON)
                 .ToImageSkia());
    } else {
        button.SetImage(views::Button::STATE_NORMAL, icon);
    }
    gfx::Size prefsize = button.GetPreferredSize();
    button.SetBounds(0, 0, prefsize.width(), prefsize.height());

    gfx::Vector2d press_point;
    if (press_pt)
        press_point = press_pt->OffsetFromOrigin();
    else
        press_point = gfx::Vector2d(prefsize.width() / 2, prefsize.height() / 2);

    // Render the image.
    scoped_ptr<gfx::Canvas> canvas(
        views::GetCanvasForDragImage(widget, prefsize));
    button.Paint(ui::CanvasPainter(canvas.get(), 1.f).context());
    drag_utils::SetDragImageOnDataObject(*canvas, press_point, data);
}

} // namespace button_drag_utils
